The science of weight lifting mechanics has until the present been quite primitive especially when considering the exercise known as the arm curl. Prior art devices of which applicant is aware for exercising the arm in a curling motion merely comprises a standard bar bell set in which the curling exercise is done while the user is standing, or the use of a dumb bell on an inclined board in which individual arms are exercised separately.
In the first case, there is a tendency to develop an oscillatory rocking motion with the body which tends to translate this momentum to serve as an aid in performing the exercise since by rocking back and forth, the bar bell can benefit from this motion and effectively decrease the weight and work done. Further, it should be apparent that as the arm pivots at the elbow, the mechanical advantage of the arm and its associated muscles changes as a function of its position to the extent that the difficulty of the exercise changes and varies as a function of the upper arm's relationship to the forearm. When using dumb bells on an inclined board, the advantage of the rocking motion has been minimized, but an additional problem is encountered in which the dumb bell can be allowed to rotate to provide torsion on the arm and thereby affect the mechanical advantage.